Alloy



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. and 15%. There appears to be some kind of Patented Feb. 9, 1926.

UNITED A STATES PATENT OFFICE.

RODERICK I... JOHNSTON,'OF PLAINFIELD, NEW JERSEY, ASSIGNOR T0 ALUMINUM DIE-CASTING- CORPORA'I'ION, A CORPORATION OF NEWJERSEY.

ALLOY.

No Drawing.

To all whom it may concern:v

Be it known that I, RODERICK L. J OHNS- TON, a citizen of the United States, and a resident of Plainfield, county of Union State of New Jersey, have invented certain new and useful Improvements in Alloys, of which the following is a specification.

This invention relates to alloys and is herein disclosed as an alloy of aluminum. tin and silicon. This alloy is well adapted to be made of commercially available materials and yields silver-white or nickelwhite castings, of a lighter color than some of the other silicon alloys, Moreover, being free from easily volatilemetals it is well adapted for such uses as diecasting where the molten metal is constantly in a suitably heated pot and is replenished from time to time during a days work. In such a pot the alloy of the present invention remains of constant composition throughout a days pouring.

I have found that an alloy of 89% aluminum, 6% of tin and 5% of silicon possesses many advantages. These proportions disregard both the usual impurities found in suitable commercial metals and alloys and some non-deleterious elements, such as the iron referred to elsewhere in this specification. The alloy, is silver-white and of good strength, well adapted to be cast either in ordinary molds or those used in die casting. It gives a very smooth finish when used for die castings, andhas the desired freeflowing qualities needful in alloys used for die casting. Moreover .it machines exceptionally well; more readily than the other silicon aluminum alloys; It is found that when used in the ordinary melting pots of die casting machines it will not absorb any deleterious amount of iron. It has a tensile strength of about 23,000 lbs. to the square inch with a 1% elongation in a standard 2-test piece.

I have found that the tin content canvary widely, as between 5% and 10%, and the silicon content can also vary as between 1% relationship between the tin and silicon. In the higher ranges of tin the best results will be obtained usually by keeping the silicon the alloy around 5%. 'In the higher Application filed December 26, 1922. Serial No. 609,102.

ranges of silicon the best results will be obtained usually by keeping the tin in the alloy around 5 or 6%-., That is, with a low content of tin a high content of silicon 15 used whereas with a high content of tin a low content of silicon is employed.

It color is desirable the silicon may be in the neighborhood of 5% to 6%. -A large proportion of silicon reduces the shrinkage, a great desideratum in large die castings since it prevents the formation of cracks in large castings.

Having thus described certain embodiments of my invention by way of example, what I claim is: p

1. An aluminum base alloy containing about 5% to about 10% of tin, a substantial amount of silicon, and the balance aluminum.

2. An aluminum base alloy containing from about 5%'to about 10% of tin, about 1% to 15% of silicon, and the balance aluminum.

3. An aluminum base alloy containing about 6% of tin, about5% of silicon and the balance aluminum. y

4. An aluminum base alloy containing from about 5% to about 10% of tin, about 5% to 6% of silicon, and the balance aluminum.

5. An aluminum base alloy containing 5% to 6% of tin, from about 5% to about 15% of silicon, and the balance aluminum.

6. An aluminum base, alloy containing and upward of aluminum, and also containing silicon and tin, each in amounts greater than about 5% and the tin less than about 10%.

7.An' aluminum base alloy containing 75% and upward of aluminum and the remainder being silicon and tin, with the usual impurities, the tin content being more than about 5% and less than about 10% and the 95 silicon content being more than about 1% and less than about 15%, a low tin content 

